Format

Parameters

source

source ADDE
dataset name and position; specify one of the following formats:

group/descriptor.position

alias.position

a position greater
than zero represents an absolute position in the dataset; a position less
than or equal to zero represents a relative position in the dataset based
on image time; for example, 0 is the most recent and -1 is the next most
recent; to use default position, do not specify .position (no
default for group/descriptor or alias; default=0 for position)

dest

destination
ADDE dataset name and absolute position; specify one of the following
formats:

group/descriptor.position

alias.position

use only positive
integers for position

tdiff

ADDE dataset
containing brightness value 0-255 that correspond to surface-ir temperature
values of -10 to 100K; see the Remarks

Keywords

BASEmap=

generic

ADDE dataset
containing single-band basemap

red green
blue

ADDE datasets
containing red, green and blue channels of basemap

BASEThreshold=

maxium gray shade value from a basemap to be considered
a map; if three datasets are specified in the BASEMAP= keyword, the value from the red channel is used
for this keyword; if the gray shade value of the basemap is less than the threshold, the transparency of the source
image is increased by 50%; this option is useful when a virtual graphic of a map outline has been burned into a
basemap using the SVGA command (default=0)

CLOUDnocloud=

minimum brightness
value for tdiff dataset to be considered a cloud; the range
is 0-255 where 0 makes the basemap disappear and 255 makes the clouds
disappear (default=40)

EU=

source basemap

name of enhancement
tables to apply to source and basemap images; source is
used only with FILT=GENERIC and basemap is used only with BASE=generic

FILTer=

GENERIC

combines generic
image and basemap; percentages of generic and basemap image are determined
using the TRANSPARENCY keyword

VISIR

combines visible,
infrared and basemap imagery; percentages of visible and infrared data
are determined by date and time of image

TDIFF

combines infrared
and basemap imagery using surface-ir temperature differences to determine
cloud/no-cloud and transparency values; see the Remarks

WVSST

combines water
vapor, sea surface temperature and basemap imagery; transparency is determined
by WV count using the enhancement table specified with WVEU keyword

IReu=

name of enhancement
table to apply to infrared image when using FILT=TDIFF

NAVele=

number of elements
between each navigation calculation; the range is 1-640 where higher
numbers increase speed by decreasing the number of calculations, but
also result in lower image quality (default=5)

SSTeu=

name of enhancement
table to apply to sea surface temperature image when using FILT=WVSST
(default=IMGRGB_SST.ET)

TRACKing=

YES

tracks image if allowed by the server; tracking allows commands
to receive data as it's being ingested by the server; commands complete when their data request has been fulfilled; tracking
is only supported on some servers (e.g., Area, GVAR and MTSAT) and it can be disabled by the server administrator

NO

does not track image so server only sends data that is
currently available (default=value of MCTRACK environment variable; if MCTRACK is not set, default=value set by server
or server administrator)

TRANSparency=

britlo brithi
pctlo pcthi

transparency values to assign low and high brightness
levels when using FILT=GENERIC; if the value for pctlo is greater
than 0, brightness values 0 to britlo are assigned transparency
values 0 to pctlo; if the value of pcthi is less than
100, brightness values brithi to 255 are assigned transparency
values pcthi to 100 (default=0 255 0 100)

WVeu=

name of enhancement
table to apply to water vapor image when using FILT=WVSST (default=IMGRGB_WV.ET)

Remarks and Examples

All source and basemap images must be the same size and cover the same geographical
region.

Each option for the FILTER keyword is described below with an example.

GENERIC

This option uses a generic image with a basemap.
With the TRANSPARENCY keyword the percentages of these two images is determined.
The following example combines a NEXRAD image with NASA's Blue Marble Next
Generation basemap.

The IMGRGB combines the NEXRAD image with the basemaps with a specific transparency
and a radar enhancement table. The IMGDISP commands and COMBINE command are
used to display the resultant image, a radar display over a basemap.

VISIR

This option uses the date and time of the imagery to determine the percentages
of visible and infrared to be used. The transparency is determined by combining
the visible and infrared image information where warm/dark pixels are very
transparent and cold/bright pixels are very opaque. This set of examples
combines a topographic basemap with visible and infrared imagery.

To create the basemap, you have to first decide on an elevation range then
use IMGOPER to reduce the 2-byte data to 1-byte. The highest point in North
America is roughly 6000 meters, so this IMGOPER scales the global basemap.

The IMGRGB combines the basemap and satellite imagery with a topography
enhancement. The IMGDISP, MAP and COMBINE commands are used to display the
resultant image. The FRMSAVE saves the image as a 24-bit jpeg file.

TDIFF

This option uses the tdiff image to determine
a cloud/no-cloud threshold and to determine the transparency of the infrared
imagery on top of a basemap. The tdiff image, which must be created
prior to running this command, must have brightness values 0-255 corresponding
to surface-infrared temperature difference values -10 to 100. For example,
commands like those below can be used to create the tdiff image.

The IMGRGB combines the satellite imagery and temperature difference image
over the basemaps. The IMGDISP commands and COMBINE command are used to display
the resultant image, the GOES infrared imagery over the basemap.

WVSST

This option requires that you create a sea surface
temperature image before running the command. Land values in the SST image
must have a value of 0. The default enhancement table for SSTEU= assumes that
SST temperature values 270 to 305 correspond to gray shades 0 to 149. Transparency
values are determined by brightness values of the water vapor image and, if
present, the enhancement table specified with WVEU=. The enhancement table
should stretch only gray shades (i.e., do not use colors). This example uses
a GOES water vapor image, the land/sea mask image, and gridded SST data.

After remapping the land/sea mask image into the desired domain, the IMGFILT
combines the land/sea mask with the SST image which leaves the land black and
the appropriate sea surface temperatures over the water.